public static List <ContactData> GetAllContacts()
        {
            List <ContactData> fromDB = null;

            using (AddressBookDB db = new AddressBookDB())
            {
                fromDB = (from g in db.Contacts.Where(x => x.Deprecated == "0000-00-00 00:00:00") select g).ToList();
            }
            return(fromDB);
        }
        public static List <GroupData> GetAllGroups()
        {
            List <GroupData> fromDB = null;

            using (AddressBookDB db = new AddressBookDB())
            {
                fromDB = (from g in db.Groups select g).ToList();
            }
            return(fromDB);
        }
        public static List <GroupData> GetGroupsByContact(ContactData cd)
        {
            List <GroupData> fromDB = null;

            using (AddressBookDB db = new AddressBookDB())
            {
                fromDB = (from gr in db.Groups
                          from gcr in db.GCR.Where(x => x.GroupId == gr.Id && x.ContactId == cd.Id)
                          select gr).Distinct().ToList();
            }
            return(fromDB);
        }
        public static List <ContactData> GetContactsInGroup(GroupData gr)
        {
            List <ContactData> fromDB = null;

            using (AddressBookDB db = new AddressBookDB())
            {
                fromDB = (from c in db.Contacts
                          from gcr in db.GCR.Where(x => x.GroupId == gr.Id && x.ContactId == c.Id)
                          select c).Distinct().ToList();
            }
            return(fromDB);
        }